How to choose a wastegate srping pressure?

[dontfeedphils]

Well I'm looking at going to a Tial 38mm external wastegate, but I've searched and searched and I can't find how to choose the correct spring pressure. My car is a 90 GSX and I'm running a 16G at about 16 psi. Thanks for any help guys.

 

[CanadianTSi]

The spring pressure determines the lowest amount of boost you can run.

I would go with a 1Bar Spring.

 

[daren_p]

Like Tyler said, the spring you choose determines the least amount of boost you can run. The springs are rated in the amount of boost you will see & not the spring tension to make things easier. So if you get a 1 bar spring, you will see right around 1 bar of boost. As a side note, I was told by Tial that its a good idea to try & get your base spring pressure closer to what your final setting will be. Currently I run the ~13 psi spring & have my MBC set to run 20 psi. I have an extra spring that if installed would make my base boost around 17.5 psi & I was told it was recommend to put the extra spring in. I believe it may give quicker up top boost response as it may keep the WG valve closed longer. I was planning on adding the extra spring in the next couple days to see if it did effect performance at all.

 

[mastervisionary]

I was wondering this as well.

-n eBay I saw most were like 30 and 40 psi so they only open above that?

 

[99gst_racer]

I was wondering this as well.

-n eBay I saw most were like 30 and 40 psi so they only open above that?

There is no such thing as a 30 or 40 PSI external wastegate. It probably said 30mm or 40mm, referring to the diameter of the valve.

 

[95ttalontsi]

i have also heard that you want to get a springs that is at least half the psi that you plan to run because if you get say a 7lb spring and you are trying to run 30 psi with your boost controller, the backpressure in the exhaust will open the wastegate and you wont ever see 30psi. I agree with canadiantsi a 1bar spring seems to work perfect.

 

[Seamus]

I would get the absolute highest possible spring. You absolutely get better results. If you ever need ot run really low boost, its probably because somehting is wrong. Why would you just not boost the car. I planned on running 25ish psi, so I bought springs to get me to about 22psi. It also can hlep with your boost dropping off. I ended up being able to tune my car about 32psi. But with the 22psi springs, my boost drops to about 27ish by redline. So I plan on reconfiguring my springs for 28ish psi and see what happens. It should help me hold closer to my target boost at redline.

 

[LandSpeed-DSM]

Just FWIW there are holset and borg warner actuators listed for north of 30psi.